Building to a Group "A" standard isn't that hard... (170hp 125#/ft) It takes a good combination of parts, and a knowledgeable engine builder. Building to an N2 standard is another story, N2 is similar O/S valves to an F/A engine.

I thought the Group A 4A-GE in Initial D was a Silvertop? It's been a while since I watched the show, though. I remember he blew the 16v going against a Lancer Evo. And right around that time Bunta was talking to his friend about his "special purchase" engine.

oldeskewltoy wrote:Building to a Group "A" standard isn't that hard... (170hp 125#/ft) It takes a good combination of parts, and a knowledgeable engine builder. Building to an N2 standard is another story, N2 is similar O/S valves to an F/A engine.

A Grp"A" should cost under $10k, while the N2 is likely over $10k

Could you go into some of the difference between the Group A and the N2 4age? Im just curious.

oldeskewltoy wrote:Building to a Group "A" standard isn't that hard... (170hp 125#/ft) It takes a good combination of parts, and a knowledgeable engine builder. Building to an N2 standard is another story, N2 is similar O/S valves to an F/A engine.

A Grp"A" should cost under $10k, while the N2 is likely over $10k

Could you go into some of the difference between the Group A and the N2 4age? Im just curious.

All the details are in the TRD Bible....

but in essence... the valve size/port size is larger(32 in vs 30.5, and 27.5 vs 25.5) the powerband is different GrpA is measured from 3k - 8k, while N2 is measured from 6k to 9k (that means cams are different - lifts mostly, GrpA required to remain @ 7.5mm, while the N2 engines ran 10mm), and the oiling system is significantly different with GrpA running wet sump, and N2 running dry sump

From memory (and I don't mind being wrong on this) back in the day when you could buy all the parts you needed from TRD, Group A engines were rated 170 hp and used EFI, wheras Group N engines were rated 210 hp using carbs and a heap of expensive parts. That is to say, almost every moving part (and a lot of non-moving parts) on the N2 build were uprated to racing spec.

The result was that Group A cars were relatively common for both race and rally all round the world, Group N never made it outside of Japan.

Cheers... jondee86

Give a person a fish, they eat for a day. Suggest they search before posting, and they learn a skill for a lifetime.

Actually N2 racing today doesn't go by any of those standards...top N2 car now which is the CBY Trueno doesn't use over sized valves or dry sump but he does use a 4.5ag kit which is bigger bore pistons and long rods...other cars are use 7a blocks and 5ag stroker kits...all rated around the 240-250ps range as well...some using Altezza 6 speeds and others still using T50 setups...

Interesting. A few years ago I spoke with a guy who had started looking for more power out of his 4AGE. He started adding parts... pistons, rods, cams and so on, and the power climbed up. Eventually he was making around 220hp which was nice, but the power band was from 8000-10000rpm. Below that it just fell on its face.

So in the end he had to admit that he had spent a butt load of cash to develop an engine that was basically useless for anything but circle track. That was one of the conversations that caused me to change direction with my AE86

Cheers... jondee86

Give a person a fish, they eat for a day. Suggest they search before posting, and they learn a skill for a lifetime.

So in the end he had to admit that he had spent a butt load of cash to develop anengine that was basically useless for anything but circle track. That was one ofthe conversations that caused me to change direction with my AE86

Would you care to elaborate? I've asked so many questions on this site, and I feel I've wasted others' generous offers of insight and experience due to my lack of experience and funding. I've managed to make a tired ae82 go faster mostly by unbolting everything not functionally essential, but now I'd like to get a little more power, and maybe put the back seats in the car. I can't afford OST's head work, lovely as it is, but I've got some oversize smallport pistons, I've ordered a light weight flywheel/clutch/p.plate assembly, and I hope to install more aggressive cams (and assume I can figure out how to time them from this site). Is there more simple (cheap) stuff I can do? Forget about the back seat and the spare? I was told when building a Ford v-8 there's no sense putting more fuel and air in if I can't get it out. Is a header worth thinking about? Does a thinner head gasket make a worthwhile change? I don't want and can't afford an engine running on the ragged edge of disaster. I'd like something stout and un-finnicky.

There are a few basic facts that have to be kept in mind when trying to extract more power out of a 4AGE engine. The first is that when Toyota decided to produce a 4-valve engine, they wanted it to be "powerful" by the standards of the day when they were competing with the likes of the Honda CRX. So the factory went to a lot of trouble to make sure that the 4AGE was as efficient as it could be to meet the sporting image of the AE86, while still being able to be driven to the mall by mom or dad.

This means that the factory cast iron exhaust manifold and two into one merge section work pretty well. There is little to be gained by going any larger than 2" dia on the exhaust. A high-flo cat and decent silencer will keep the back pressure down. A cheap header is money down the drain.

The head design featured the popular at the time TVIS dual intake runner system which helped to maintain some performance at low rpm while allowing the engine to flow enough air for high rpm operation. The intake side of the engine will not be a restriction with the kind of modifications you are looking at just now. Keep the TVIS system operative.

Compression is your friend when looking for more power, so if you can fit the smallport pistons (which means finding a way to mate 20mm pistons to 18mm bigport rods) you are heading in the right direction. The alternative, which may be cheaper, is to take a cut off the head and use a thinner gasket. Bearing in mind that a thinner (MLS) gasket may also require a cleanup cut off the block to make sure the mating surfaces are suitably prepared. A CR of around 10.5:1 would be nice.

More compression means that you can use cams with more duration or lift, and personally I would suggest you aim for as much lift as you can get (say 8.5mm ) and around 272 duration. Anything less and your butt dyno will be disappointed.

Now the sticking point The engine computer (ECU) is factory set (non-adjustable) and programmed to work with stock compression and cam timing. This means that once you modify these two parameters, neither your fuel mixture nor ignition timing will be correct. So you need to factor into your budget some kind of aftermarket ECU. Without proper engine management you run a real risk of doing a lot of work for little or no gain.

A lighter flywheel is always nice, as it makes the engine more responsive. Standard clutch and pressure plate will handle a modest increase in power and normal tuneup items like plugs, filters and oil are a good investment.

There are as many opinions as there are active members on these forums, and I am sure there will be other worthy suggestions and tips to come

Cheers... jondee86

Give a person a fish, they eat for a day. Suggest they search before posting, and they learn a skill for a lifetime.

oldae82 wrote:So in the end he had to admit that he had spent a butt load of cash to develop anengine that was basically useless for anything but circle track. That was one ofthe conversations that caused me to change direction with my AE86

Would you care to elaborate? I've asked so many questions on this site, and I feel I've wasted others' generous offers of insight and experience due to my lack of experience and funding. I've managed to make a tired ae82 go faster mostly by unbolting everything not functionally essential, but now I'd like to get a little more power, and maybe put the back seats in the car. I can't afford OST's head work, lovely as it is, but I've got some oversize smallport pistons, I've ordered a light weight flywheel/clutch/p.plate assembly, and I hope to install more aggressive cams (and assume I can figure out how to time them from this site). Is there more simple (cheap) stuff I can do? Forget about the back seat and the spare? I was told when building a Ford v-8 there's no sense putting more fuel and air in if I can't get it out. Is a header worth thinking about? Does a thinner head gasket make a worthwhile change? I don't want and can't afford an engine running on the ragged edge of disaster. I'd like something stout and un-finnicky.

This really needs a posting of its own..... Jondee did hit the nail squarely... the original TVIS engines NEED more static compression. The rest can all be argued...

jondee86 wrote:Interesting. A few years ago I spoke with a guy who had started looking for more power out of his 4AGE. He started adding parts... pistons, rods, cams and so on, and the power climbed up. Eventually he was making around 220hp which was nice, but the power band was from 8000-10000rpm. Below that it just fell on its face.

Cheers... jondee86

This is a very relative discussion. A lot of people will use words like streetable saying that a 240 hp Forumula Atlantic won't be "streetable" or "will fall on it's face". If built properly said motor should make similar power to a stock 4A at least over 3000 RPM if not lower than that. In this case it should be considered at least as "streetable" as a stock 4AGE. It's just that when the motor makes double stock hp at redline stock power at 3000 RPM will feel a lot slower. Then there is the fact that a good turbo setup or a larger displacement motor could make double that hp from 3000 to redline which would make a big difference in both feel and performance.

oldae82 wrote:So in the end he had to admit that he had spent a butt load of cash to develop anengine that was basically useless for anything but circle track. That was one ofthe conversations that caused me to change direction with my AE86

Would you care to elaborate? I've asked so many questions on this site, and I feel I've wasted others' generous offers of insight and experience due to my lack of experience and funding. I've managed to make a tired ae82 go faster mostly by unbolting everything not functionally essential, but now I'd like to get a little more power, and maybe put the back seats in the car. I can't afford OST's head work, lovely as it is, but I've got some oversize smallport pistons, I've ordered a light weight flywheel/clutch/p.plate assembly, and I hope to install more aggressive cams (and assume I can figure out how to time them from this site). Is there more simple (cheap) stuff I can do? Forget about the back seat and the spare? I was told when building a Ford v-8 there's no sense putting more fuel and air in if I can't get it out.

Sounds like something a V8 builder would say. Oversimplified inaccurate statement that contains some grain of truth. If you have a restriction on the exhaust side that will prevent you from getting anything more in on the intake side so intake side modifications would not allow more air in if the exhaust side is the primary restriction. With that said as mentioned the stock exhaust is pretty decent for near stock power levels. More importantly there are no off the shelf headers or exhausts that have proven repeatable gains so if you are ready to get more out of your exhaust system your best bet would be something custom designed and built. Then ideally a few versions tested to see which perform better with your setup. Not a cheap or easy project. Fortunately there is a lot of room to grow before you need to worry about it. If your goal is best $/hp ratio then turbo is the clear choice. It will cost a little more up front than the mods you suggest but will by far give you the best gains per dollar spent. If turbo is not an option then you are roughly on the right path but the quality and forethought in will equal the results you get out. Just throwing random parts at a build will get you uninspiring results. This is the route that most 4A owners take and it is the reason the 4A has such a reputation of being a disappointing and expensive motor to get power out of. Build it right and it's not bad but it is still a 1.6 liter motor so you can't expect to build an NA 2GR killer for $3k. You could build a turbo 2GR killer for $3k though so that is worth keeping in mind. One thing that particularly sucks about NA builds is they aren't condusive to building in stages. Pick your compression for your current cam then go with a bigger cam and your compression will no longer be ideal. Pick the compression for the cam you want in the future and it will be too high for your current cam. Turbo builds are great because they take very well to building in stages. Throw a turbo on a stock motor and you can push it till you reach the limits of the engine management. Add aftermarket engine management and you can push it to the limits of the stock internals. Upgrade the internals and you can push it to the limits of your turbo. Upgrade the turbo and the limits are pretty much dependent on the size you pick.

Yoshimitsuspeed is absolutely correct above. Just because an engine makes its peak power at 9000-10000 rpm doesn't mean it can't move under its own power below that.A typical Atlantic type is making around:

120bhp at 4800, 145bhp at 5800195bhp at 6800220bhp at 7800240bhp at 8800250bhp at 9800

My engine is just fine driving around downtown SF. Good oil pressure in traffic, good coolant temp. If I can simply ignore the noise at idle, the rattle from the clutch & the smell of the gantry injection I could drive it all day. But I can't. I love driving it as much as possible & it's surprisingly easy to drive, even with 12:1 compression, a tiny flywheel & a 2 disc clutch with no hub springs.

The only thing that stops me driving it more is the fear of it being stolen, other than that I'd drive it 3-4 days per week. Oh, heating the oil before use is a pain in the A as well. I find it to be no less drivable than anything else out there that has been modified to perform at a high level.

Billy_Andrea wrote:120bhp at 4800, 145bhp at 5800195bhp at 6800220bhp at 7800240bhp at 8800250bhp at 9800

Interesting that the engine power keeps going up way after peak torque has been and gone. I guess that this is done on purpose because the engine is primarily used at high rpm's (in FA), and close ratio gears will keep the engine turning in the 7500-10000 rpm range.

jondee86 wrote:Interesting that the engine power keeps going up way after peak torque has been and gone. I guess that this is done on purpose because the engine is primarily used at high rpm's (in FA), and close ratio gears will keep the engine turning in the 7500-10000 rpm range.

Torque on it's own is irrelevant. All that matters is making as much power as possible over a wide enough range to cover the gear ratios. HP will continue to climb as long as torque doesn't fall faster than torque x RPM /5252.